In
the Haggadah we read Rabbi Levi Yitzchak of Berdichev talking about the fourth
son, the one who "did not know how to ask" -- traditionally thought
of as the child furthest removed from the events of the night:

"The
one who knows not how to ask, that is myself, Levi Yitzchak of Berditchev,
I do not know how to ask you, Lord of the world, and even if I did know, I
could not bear to do it. How could I venture to ask you: Why ... we are driven
from one exile into another, why our foes are allowed to torment us so much?

"But
in the Haggadah the parent of the one who does not know how to ask is told:
'It is for you to disclose the answer to the child.'

"And
the Haggadah refers to the Torah in which it is written, 'And you should tell
your son' (Exodus 13). '

"Lord
of the world, am I not your child?" (Even if I cannot begin to formulate
the questions, you can begin to answer them for me.)